Question: At a party to celebrate a successful school play, the drama club bought $9$ large pizzas. Each pizza had $s$ slices. All together, there were $72$ slices of pizza for the club to share. Write an equation to describe this situation. How many slices does each pizza have?
There are $9$ pizzas at the party. We are calling the number of slices in each pizza ${s}$. There were a total of ${72}$ slices of pizza. We can represent the total number of slices of pizza as a product: ${9} {s}$ We know that there were a total of ${72}$ slices of pizza. We can set these two expressions equal to describe this situation with an equation: ${9} {s} = {72}$ Other ways to represent the situation with an equation include: $\dfrac{{72}}{ s}=9$ or $\dfrac{{72}}{ 9}= s$. Now we can solve for ${s}$. Divide both sides by ${9}$ to get $ s$ by itself. $\begin{aligned}\dfrac{ {9}{s}}{9} &= \dfrac{{72}}{9} \\\\ {s} &= 8 \end{aligned}$ The following equation matches this situation: $9s = 72$ Each pizza has $8$ slices.